How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRR’s Rehabilitation Engineering Research Centers

Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a “total approach to rehabilitation”, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970’s, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program

Experimental Analysis and Modeling of Robot-Tissue Contact Mechanics for In Vivo Mobility

Robotic mobility within the gastrointestinal (GI) tract is an intriguing concept, which has received wide attention from within the research community over the past ten years. Capsule endoscopes (CEs) exist commercially, but lack an active mobility system, rendering them as passive devices. These passive devices are only capable of observational procedures, and are limited by the passive speed (dependent on intestinal peristalsis), inability to control orientation, and vulnerability to retention, requiring surgical removal in severe cases. Additionally, passive capsules take photos throughout their journey, resulting in a compilation of thousands of images, which can take the attending physician hours to review. Due to these drawbacks, traditional endoscopes remain as the most popular intervention for GI related procedures. A traditional endoscope consists of a long flexible tube with a camera on the end of it. The tube usually has ports for tools, insufflation and irrigation. A user interface is located on the operator end of the scope, and can be manipulated to steer the tip of the scope. The scope is inserted through the oral or rectal orifice and is advanced by pushing the scope. As the scope is pushed, frictional forces can accumulate, resulting in advancement of the body of scope without advancement of the tip, termed looping. Looping results in distention of the bowel wall, pain for the patient and in rare cases perforation. A robotic capsule endoscope (RCE) for oral endoscopies or robotic capsule colonoscope (RCC) for rectal colonoscopies is a capsular device (tethered or non-tethered) that propels itself through the GI tract. Self-propulsion could result in less looping, less pain for the patient, more ergonomic operation for the physician, control over capsule position and orientation, and the addition of diagnostic and therapeutic tools over existing passive CEs. This work focuses on the contact mechanics of robot-tissue interaction in the GI tract with the goal of furthering the understanding of the physical problem so that more efficient and optimized mobility systems may be designed for RCEs and RCCs. This work also focuses on the design of an RCC which uses micro-patterned polydimethylsiloxane (PDMS) treads as a mobility method. The thesis is divided into nine chapters. Chapter 1 provides an overview of capsule and flexible endoscope technology as it relates to screening, diagnostics and therapy. A thorough overview of existing mobility methods (both commercial and experimental) for RCEs is also presented along with a background on micro-patterning for friction enhancement. Chapter 2 presents the qualitative analysis of micro-patterned treads through the development and in vivo testing of a series of two-wheeled robots as well as a testing apparatus for quantitatively evaluating micro-patterned robotic wheels in a static environment. Chapter 3 presents the development of a novel testing apparatus for evaluating robotic wheels in a dynamic environment, and results from data collected using the apparatus. The results from this device suggested that an automated dynamic testing environment would be necessary for deeper understanding of robot-tissue interaction. Chapter 4 presents the development of an automated traction measurement (ATM) platform for evaluation of robotic wheels on synthetic or biological tissue substrates as a function of normal force, rotational velocity and linear velocity. An empirical model for predicting traction force was also developed and validated using data collected from the ATM platform. Chapter 5 presents a study on the relationship between substrate height (i.e., stiffness), robot wheel tread pillar diameter, and the resulting generated traction force using the ATM platform for experimental collection and finite element modeling for validation. Chapter 6 presents the design and in vivo testing of an RCC which utilizes micro-patterned treads as a mobility method. The tethered prototype featured an onboard camera, and white and infrared (IR) light sources. Chapter 7 presents the development and experimental validation of an analytical model for predicting the drag force necessary to move a cylindrical capsule endoscope through the GI tract. Chapters 8 and 9 address discussion, conclusions, and future work. The work in this thesis has advanced the understanding of the contact mechanics for robot-tissue interface, especially pertaining to micro-patterned surfaces, and has resulted in several tools, both hardware and software, for measuring and modeling traction and drag force for capsule endoscope mobility methods. Additionally, this work has resulted in a novel RCC design prototype, which has the potential to evolve into a clinically viable device

Magnetically driven medical devices: A review

A widely accepted definition of a medical device is an instrument or apparatus that is used to diagnose, prevent or treat disease. Medical devices take a broad range of forms and utilize various methods to operate, such as physical, mechanical or thermal. Of particular interest in this paper are the medical devices that utilize magnetic field sources to operate. The exploitation of magnetic fields to operate or drive medical devices has become increasingly popular due to interesting characteristics of magnetic fields that are not offered by other phenomena, such as mechanical contact, hydrodynamics and thermodynamics. Today, there is a wide range of magnetically driven medical devices purposed for different anatomical regions of the body. A review of these devices is presented and organized into two groups: permanent magnetically driven devices and electromagnetically driven devices. Within each category, the discussion will be further segregated into anatomical regions (e.g., gastrointestinal, ocular, abdominal, thoracic, etc.)

Frictional resistance model for tissue-capsule endoscope sliding contact in the gastrointestinal tract

Wireless capsule endoscopes are becoming prevalent in the medical field as screening, diagnostic and therapeutic tools within the gastrointestinal (GI) tract. However, state-of-the art capsules lack active locomotion systems, which could improve accuracy and broaden applications. The actuation efficiency for direct capsule-tissue contact depends on the frictional resistance between the capsule and the intestinal wall. A model for predicting the resistance force on a capsule was developed and experimentally validated by performing drag force experiments using various cylindrical capsule design parameters and tissue properties. Of the design parameters studied, capsule edge radius influences frictional resistance the most. The average normalized root-mean-square error between the model and experimental results is 6.25%. These results could lead to optimized capsule endoscope actuation systems

Development and Preliminary Investigation of a Semiautonomous Socially Assistive Robot (SAR) Designed to Elicit Communication, Motor Skills, Emotion, and Visual Regard (Engagement) from Young Children with Complex Cerebral Palsy: A Pilot Comparative Trial

Through play, typically developing children manipulate objects and interact with peers to establish and develop physical, cognitive, language, and social skills. However, children with complex disabilities and/or developmental delays have limited play experiences, thus compromising the quality of play and acquisition of skills. Assistive technologies have been developed to increase opportunities and level of interaction for children with disabilities to facilitate learning and development. One type of technology, Socially Assistive Robotics, is designed to assist the human user through social interaction while creating measurable growth in learning and rehabilitation. The investigators in this study designed, developed, and validated a semiautonomous Socially Assistive Robot to compare with a switch-adapted toy to determine robot effectiveness in quantity of, changes in, and differences in engagement. After interacting with both systems for three sessions each, five of the eight subjects showed a greater level of positive engagement with the robot than the switch-adapted toy, while the remaining three subjects showed slightly higher positive engagement with the toy. The preliminary results of the study suggest that Socially Assistive Robots specifically designed for children with complex cerebral palsy should be further researched and utilized to enrich play interactions and skill development for this population